It is known to use MMVF as an insulation material to provide acoustic or heat insulation. The MMVF are usually formed into an MMVF substrate which is formed as a bonded web comprising the MMVF and a cured binder composition. The requirements for an MMVF substrate to withstand heat vary depending on the ultimate use of the MMVF substrate. For example, in marine and industrial applications, the MMVF substrate used as technical insulation is required to withstand high temperatures such as greater than 950° C. for prolonged periods of time, such as at least 30 minutes, when used for fire protection, or temperatures in the range of 100-650° C. in continuous use, when used for high temperature technical installations. Building regulations or other regulations in different countries determine the specification required for technical insulation. The lower the thermal conductivity, expressed in terms of the lambda value, of an MMVF substrate at a given temperature, the more resistant the MMVF substrate is to transmitting heat.
The air flow resistivity of an MMVF substrate should be as high as possible to reduce the amount of air that can pass through the MMVF substrate. A high air flow resistivity for a product indicates an improved ability of the MMVF substrate to withstand heat.
One way to increase the resistance of an MMVF substrate to temperature is to increase the volume of MMVF substrate. This has the effect of increasing the time required for heat to transfer across an MMVF substrate. Increasing the volume of the MMVF substrate however is undesirable as it increases the cost of the technical insulation, increases the space required for the technical insulation and increases the environmental impact of producing the technical insulation.
It is desirable that an MMVF substrate is easy to handle and causes little irritation to the skin.
There is a need to produce an MMVF substrate with a lower thermal conductivity at a given temperature, for example at 300° C. or higher. Further, there is a need for an MMVF substrate with increased air flow resistivity. Further, there is a need for an MMVF substrate with improved skin-friendliness. Further there is a need to produce an MMVF substrate which is environmentally friendly. The present invention solves these problems.